fix: Design-PATCH fehlte Bearer-Token + Race Condition bei Fertigstellen

- Neues updateDbPicture() in api.ts mit korrektem Bearer-Header
- Design-onChange nutzt updateDbPicture statt rohem fetch (kein Bearer-Bug mehr)
- finishPicture sendet status + design in einem PATCH (kein Race Condition)
- app.py: get_json(force=True, silent=True) für db-pictures PATCH

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/pages/DrawIt.tsx

@@ -4,6 +4,7 @@ import BlurhashCanvas from '../components/BlurhashCanvas'
 import Topbar from '../components/Topbar'
 import {
   getDbPictures,
+  updateDbPicture,
   updateDbPictureStatus,
   getDbObjects,
   createDbObject,
@@ -225,7 +226,11 @@ export default function DrawIt() {
     if (!currentPicture || !token) return
     setFinishing(true)
     try {
-      await updateDbPictureStatus(currentPicture.id, 'objects_created', token)
+      // Save status + current design in one call to avoid race conditions
+      await updateDbPicture(currentPicture.id, {
+        status: 'objects_created',
+        design: currentPicture.design ?? null,
+      }, token)
       setPictureList(prev => prev.filter(p => p.id !== currentPicture.id))
       setCurrentIndex(i => Math.max(0, i - 1))
       setObjects([])
@@ -419,14 +424,14 @@ export default function DrawIt() {
                 value={currentPicture.design || ''}
                 onChange={async e => {
                   const value = e.target.value
-                  setPictureList(prev => prev.map(p => p.id === currentPicture.id ? { ...p, design: value || null } : p))
+                  const design = value || null
+                  setPictureList(prev => prev.map(p => p.id === currentPicture.id ? { ...p, design } : p))
                   try {
-                    await fetch(`/api/directus/db-pictures/${currentPicture.id}`, {
-                      method: 'PATCH',
-                      headers: { 'Content-Type': 'application/json', Authorization: token ?? '' },
-                      body: JSON.stringify({ design: value || null }),
-                    })
-                  } catch (e) { console.error(e) }
+                    await updateDbPicture(currentPicture.id, { design }, token!)
+                    showStatus('Design gespeichert.')
+                  } catch (e) {
+                    showStatus('Fehler beim Speichern des Designs.', true)
+                  }
                 }}
                 style={{
                   width: '100%', padding: '6px 8px', borderRadius: 'var(--r-sm)',